Changing version back to 2021-06 (#15305)

* Updating version in readme

* Updating swagger version

specification/recoveryservicesbackup/resource-manager/readme.md

@@ -28,7 +28,7 @@ These are the global settings for the RecoveryServicesBackup API.
 title: Recovery Services Backup Client
 description: Open API 2.0 Specs for Azure RecoveryServices Backup service
 openapi-type: arm
-tag: package-2021-04
+tag: package-2021-06
 csharp-sdks-folder: ./Generated/CSharp
 python-sdks-folder: ./Generated/Python
 go-sdk-folder: ./Generated/Golang